JP7382927B2 - toothbrush - Google Patents

Description

The present invention relates to a toothbrush.
This application claims priority based on Japanese Patent Application No. 2018-105172 filed in Japan on May 31, 2018, the contents of which are incorporated herein.

As a toothbrush that improves the operability of the toothbrush in the oral cavity and improves the feeling of cleaning narrow areas such as molars in the oral cavity, a toothbrush having a thin head portion with a thickness of about 2 to 3 mm is known (Patent Document 1). As a toothbrush that can gently massage the gums, there is a known toothbrush in which large-diameter bristle bundles with a diameter of 1.8 mm or more are implanted into bristle holes by driving a flat wire so that brushing pressure can be easily dispersed (Patent Document 2).

Japanese Patent Application Publication No. 2011-4852 JP2012-34844A

However, when forming a large-diameter tufting hole in a thin head portion, the depth of the tufting hole becomes shallow, so that the force of fixing the bristle bundle by the flat wire becomes low. Therefore, the hair transplantation strength (the strength at which a hair bundle comes off) and the hair shedding strength (the strength at which a single hair comes off) decreases.

One possible method to increase the fixing force of the hair bundle is to lengthen the flat wire, but if the flat wire is lengthened into the thin head, cracks may occur between the flat wires driven into adjacent tuft holes in the head. This can easily cause cracks and whitening in the head. The larger the diameter of the tufting hole, the greater the impact applied to the head during tufting, making cracking and whitening more likely to occur.

The present invention suppresses cracking and whitening of the head part even if the head part is thin and has excellent intraoral operability and has large diameter hair bundles that are effective in improving the massage experience. An object of the present invention is to provide a toothbrush that can sufficiently secure the fixing force of the bristle bundle by the flat wire.

The present invention has the following configuration.
[1] A handle body made of resin including a head portion in which a plurality of tuft holes are provided on the tuft surface, and each of the tuft holes is provided with a tufted portion in which a hair bundle is implanted by driving a flat wire. A toothbrush with
The thickness of the head portion is 2 mm or more and 4 mm or less,
The ratio of the total number of large-diameter tufting holes with a diameter of 1.8 mm or more to the total number of tufting holes provided on the tufting surface is 10% or more,
Two or more of the large diameter tuft holes are arranged in the longitudinal direction of the handle body,
At least one set of the large-diameter tuft holes adjacent in the longitudinal direction has a ratio of stress generation parameter P ₁ expressed by the following formula 1 to the longitudinal stress relaxation parameter P 2 expressed by the following formula ₂ from 20 to A toothbrush that satisfies the condition of 30%.
P ₁ = (S _A - S _B ) x h ... Formula 1
P ₂ =S _C ×D ...Formula 2
(However, in the above formulas 1 _and 2, S _A is the area (mm ² ) of the circumcircle of the flat line driven into the large diameter tufting hole when viewed from the front. is the opening area (mm ² ) of the tufting hole. h is the distance (mm) from the tufting surface to the lower end of the flat wire driven into the large diameter tufting hole in side view. _SC is , the area of the flocking surface surrounded by the opening edge of each of the large-diameter flocking holes adjacent in the longitudinal direction and two tangents that touch and do not intersect any of the adjacent large-diameter flocking holes ( mm ² ). D is the thickness (mm) of the head portion.)
[2] The toothbrush according to [1], wherein the stress generation parameter P ₁ is 2.3 to 4.0.
[3] At least one of the large-diameter tuft holes satisfies the condition that the short axis stress relaxation parameter P ₃ expressed by the following formula 3 is from 2.0 to 5.5, [1] or [2] The toothbrush described in.
P ₃ =(S _D ×D)/d...Formula 3
(However, in the above formula 3, S _D is the flocking surface surrounded by two tangent lines drawn parallel to the short axis direction of the large diameter flocking hole and the edges on both sides of the head section in the short axis direction. The area (mm ² ) of region i surrounded by the two tangent lines and the edges on both sides _S ( _D is the thickness (mm) of the head portion. d is the width (mm) of the head portion.)
[4] The large-diameter tufting hole and the small-diameter tufting hole having a diameter of less than 1.8 mm are formed on the tufting surface,
For all the large-diameter tuft holes, when a straight line is drawn parallel to the short axis direction passing through the center of the large-diameter tuft hole when viewed from the front, the straight line is 50% or more of the total number of these straight lines. is a straight line that does not pass through the center of the small-diameter tuft holes, the toothbrush according to any one of [1] to [3].

The toothbrush of the present invention has a thin head section that is easy to operate in the oral cavity, and even though it has large-diameter bristle bundles that are effective in improving the feeling of massage, cracking and whitening are suppressed in the head section. At the same time, the fixing force of the flat wire to the hair bundle is sufficiently ensured.

FIG. 1 is a front view showing an example of a toothbrush of the present invention. FIG. 2 is an enlarged front view of the head portion of the toothbrush shown in FIG. 1. FIG. Note that hair strands and flat lines are omitted. 3 is a sectional view taken along line AA of the toothbrush shown in FIG. 2. FIG. Note that hair strands and flat lines are omitted. It is a front view explaining stress generation parameter _P1 and long-axis stress relaxation parameter _P2 . Note that the hair strands are omitted. 5 is a sectional view illustrating a stress generation parameter P ₁ and a long axis stress relaxation parameter P ₂ , and is a BB sectional view in FIG. 4. FIG. Note that the hair strands are omitted. It is a front view explaining stress generation parameter _P1 and long-axis stress relaxation parameter _P2 . Note that the hair strands are omitted. FIG _{. 3} is a front view illustrating the short-axis stress relaxation parameter P3. Note that hair strands and flat lines are omitted. FIG. 3 is a cross-sectional view showing how hair bundles are implanted in tuft holes formed on the tuft surface. It is a front view showing other examples of the toothbrush of the present invention. It is a front view showing other examples of the toothbrush of the present invention. It is a front view showing other examples of the toothbrush of the present invention. It is a front view showing other examples of the toothbrush of the present invention. It is a front view showing other examples of the toothbrush of the present invention. It is a front view showing other examples of the toothbrush of the present invention. It is a front view showing other examples of the toothbrush of the present invention. It is a front view showing other examples of the toothbrush of the present invention.

Hereinafter, an example of the toothbrush of the present invention will be shown and explained in detail. Note that the dimensions of the figures illustrated in the following description are merely examples, and the present invention is not necessarily limited thereto, and can be practiced with appropriate changes within the scope of the gist thereof. .

As shown in FIGS. 1 to 3, the toothbrush 1 of this embodiment includes a handle body 1a made of resin. The handle body 1a is formed of a head portion 10, a neck portion 12, and a handle portion 14.

The neck portion 12 extends to the rear end side of the head portion 10 in the longitudinal direction. The neck portion 12 is a portion that connects the handle portion 14 and the head portion 10.
The handle portion 14 extends to the rear end side of the neck portion 12 in the longitudinal direction. The handle portion 14 is a portion that is held by the user.
The handle body 1a may be one in which the head portion 10, the neck portion 12, and the handle portion 14 are integrally molded, or may be one in which any of them are separately molded and joined.

In the present invention, if the distance in the longitudinal direction between the tip of the outer edge of the tuft hole disposed on the most distal side and the tip of the head section is L1 (Fig. 2), then the rear end of the head section is located on the most proximal side. It is a position a distance L1 from the rear end of the outer edge of the tufting hole to the rear end side in the longitudinal direction.
The head portion 10 has a flocked surface 10a on one side in the thickness direction.
A plurality of circular first tufting holes 11a and second tufting holes 11b are formed in the tufting surface 10a of the head portion 10. The head portion 10 of the toothbrush 1 is provided with a flocked portion 18. In the flocking section 18, a first hair bundle 16a is planted in each of the plurality of first hair planting holes 11a, and a second hair bundle 16b is planted in each of the plurality of second hair planting holes 11b.

In the toothbrush 1, as shown in FIGS. 4 to 6 and FIG. 8, a first bristle bundle 16a and a plurality of bristles 15 bundled and folded in half are placed in each of the first bristle implantation hole 11a and the second bristle implantation hole 11b, respectively. The second hair bundle 16b is implanted by driving a flat wire 20. Thus, the toothbrush of the present invention is a toothbrush with flat wire flocking.

The thickness D (FIG. 3) of the head portion 10 is 2 mm or more and 4 mm or less, preferably 2.5 mm or more and 3.5 mm or less. When the thickness of the head portion 10 is less than or equal to the upper limit of the above range, the toothbrush 1 has excellent operability in the oral cavity and is highly effective in cleaning narrow spaces in the oral cavity such as molars. When the thickness of the head portion 10 is equal to or greater than the lower limit of the above range, cracking and whitening of the head portion can be suppressed, and hair bundle removal strength can be ensured.
Note that the range of the thickness D of the head section means that the thickness is within the range no matter where the thickness is measured on the head section.

The width d (FIG. 2) of the head portion 10 is preferably 6 to 16 mm, more preferably 8 to 15 mm, and even more preferably 10 to 12 mm. If the width of the head portion 10 is equal to or greater than the lower limit of the above range, even if a plurality of large-diameter tuft holes are arranged in the short axis direction, it is easy to ensure a sufficient pitch between the tuft holes, thereby preventing cracking or whitening of the head portion. easy to suppress. Furthermore, it is possible to arrange the hair bundles to be suitable for cleaning the entire oral cavity by making use of the large diameter hair bundles. If the width of the head portion 10 is less than or equal to the upper limit of the above range, the intraoral operability, which is an advantage of a thin head portion, is not likely to be impaired.
Note that the range of the width d of the head section means that the maximum width of the head section is within the range. Furthermore, in this specification, a numerical range represented by "~" means a numerical range that includes the numerical values before and after ~ as the lower limit and upper limit.

The length of the head portion 10 is preferably 10 to 33 mm, more preferably 12 to 28 mm. If the length of the head portion 10 is equal to or greater than the lower limit of the above range, even if a plurality of large-diameter tufted holes are arranged in the longitudinal direction, the distance between the holes can be easily ensured, and cracking and whitening of the head portion can be suppressed. It's easy to do. Furthermore, it is possible to arrange the hair bundles to be suitable for cleaning the entire oral cavity by making use of the large diameter hair bundles. If the length of the head portion 10 is equal to or less than the upper limit of the above range, the intraoral operability, which is an advantage of a thin head portion, is not likely to be impaired.

In the present invention, the plurality of tufting holes formed on the tufting surface of the head portion may have a single diameter, or may be a combination of tufting holes having different diameters. When combining tuft holes with different diameters, it is preferable to make the diameters of the tuft holes aligned in the longitudinal direction the same in order to maintain a constant contact feeling with the bristle bundle when brushing the toothbrush in the longitudinal direction. Further, from the viewpoint of making it easier to feel the sensation of massaging the gums, it is preferable to arrange the tufting holes having a larger diameter on the outside in the short axis direction, where the brushing pressure can be easily dispersed. Furthermore, in order to further enhance the feeling of cleaning molars by taking advantage of the thin head part, and to achieve both the feeling of massage and the like, it is preferable to arrange the bristle bundles with a small diameter, which are responsible for the cleaning effect, on the inner side in the short axis direction. Note that the short axis direction is a direction parallel to the flocking surface and orthogonal to the long axis direction.
The arrangement pattern of the tufted holes is not particularly limited, and examples include a staggered pattern and a lattice pattern.

In the head portion of the toothbrush of the present invention, each tufting hole is formed such that two or more large-diameter tufting holes having a diameter of 1.8 mm or more are lined up in the longitudinal direction of the handle body.
In addition, "the tufting holes are lined up in the major axis direction" means that two tangent lines parallel to the major axis direction are drawn so as to touch both sides of any tufting hole in the minor axis direction when the head is viewed from the front. This means that another tuft hole is formed so as to at least partially overlap the area sandwiched between the two tangent lines. The mode in which the tuft holes are lined up in the longitudinal direction includes not only the mode in which the tuft holes are lined up linearly so that the center of another tuft hole is located on a straight line parallel to the longitudinal direction passing through the center of any tuft hole. Also includes an embodiment in which the center of any tuft hole is located at a position offset from a straight line parallel to the longitudinal direction passing through the center of the tuft hole, and other tuft holes are formed side by side so as to partially overlap the area. It will be done.
Similarly, "the tuft holes are lined up in the short axis direction" means that two tangents parallel to the short axis direction are drawn so as to touch both sides of any tuft hole in the long axis direction when the head is viewed from the front. This means that another tuft hole is formed so as to at least partially overlap the area sandwiched between the two tangent lines.

In this example, as shown in FIG. 2, five large-diameter first tuft holes 11a with a diameter of 1.8 mm or more are arranged in the long axis direction on each side of the tuft surface 10a of the head part 10 in the short axis direction. It is formed one by one. A total of 17 small-diameter second tuft holes 11b with a diameter of less than 1.8 mm are formed in three rows in the long axis direction in the central part of the tuft surface 10a inside the first tuft holes 11a in the short axis direction. There is. The small-diameter second tuft holes 11b are formed in a staggered manner.

In the present invention, large-diameter bristle holes with a diameter of 1.8 mm or more are arranged on the outside in the short-axis direction of the bristle-planting surface of the head part in the long-axis direction along the side edge of the head part, and these large-diameter tuft holes It is preferable to arrange the tufts so that they sandwich the tuft holes in the center. In the toothbrush 1, a small-diameter second tufting hole 11b in the center is sandwiched between two rows of large-diameter first tufting holes 11a formed in the longitudinal direction along the side edge of the head portion 10. Thereby, the feeling of massaging the gums when brushing can be enhanced.
In the present invention, the small diameter tuft holes in the center may be sandwiched between one row of pairs of large diameter tuft holes, or may be sandwiched between two rows of pairs of large diameter tuft holes.
In addition, in the present invention, a plurality of large diameter tuft holes are formed in the center of the tuft surface of the head in the short axis direction, and small diameter tuft holes are formed on both sides of the large diameter tuft holes in the short axis direction. You may.

In the toothbrush 1, the large-diameter first tufting hole 11a and the small-diameter second tufting hole 11b are arranged in the short axis direction of the head portion 10, and the center of the first tufting hole 11a and the center of the second tufting hole 11b are aligned. They are formed so that they do not lie on the same straight line parallel to the minor axis direction.

In the present invention, when forming large-diameter tuft holes and small-diameter tuft holes on the tuft surface of the head, the center of the large-diameter tuft hole and the center of the small-diameter tuft hole are aligned in the short axis direction, as in this example. Preferably, they do not lie on the same parallel straight line. In other words, even when large-diameter tuft holes and small-diameter tuft holes are arranged in the short axis direction, it is preferable that the centers of the large-diameter tuft holes and the small-diameter tuft holes are shifted from each other in the short-axis direction. . Thereby, even if a plurality of large-diameter tuft holes and small-diameter tuft holes are formed in the short axis direction, it is easy to ensure a sufficient pitch of the tuft holes, making it difficult for cracks to occur in the head portion.

When two or more large diameter tuft holes are formed in the short axis direction of the head, the centers of the large diameter tuft holes are not on the same straight line parallel to the short axis direction. It is preferable to do so. When forming two or more small diameter tuft holes in the short axis direction of the head, make sure that the centers of the small diameter tuft holes are not on the same straight line parallel to the short axis direction. It is preferable to do so.
In the present invention, in particular, all the tuft holes arranged in the short axis direction of the head part are formed offset from each other so that the center of another tuft hole does not exist on a straight line passing through the center of any tuft hole. preferable.

The diameter of the first tufting hole 11a, which has a large diameter of 1.8 mm or more, is preferably 1.8 to 3.2 mm, more preferably 2.0 to 2.5 mm. If the diameter of the first tufting hole 11a is at least the lower limit of the above range, the feeling of massaging the gums will be improved. If the diameter of the first tufting hole 11a is below the upper limit of the range, it is possible to prevent the folded part of the tuft under the flat line from becoming thicker when the tuft is planted, and the flat line can be adjusted to the depth of the tufting hole. Since it is possible to drive deeply in the direction, it is easy to ensure the hair bundle removal strength and single hair removal strength, and it is also easy to suppress cracking and whitening of the head part.
It is preferable that the diameters of the large-diameter tuft holes arranged in the longitudinal direction are the same.

The diameter of the second tufting hole 11b having a small diameter of less than 1.8 mm is preferably 1.0 to 1.7 mm, more preferably 1.2 to 1.5 mm. If the diameter of the second bristle implant hole 11b is equal to or larger than the lower limit of the above range, the rigidity of the bristle bundle necessary for cleaning dental plaque can be ensured. If the diameter of the second bristle-planting hole 11b is equal to or less than the upper limit of the above range, it is possible to ensure appropriate bending of the bristle bundle necessary for cleaning dental plaque.
It is preferable that the diameters of the small diameter tufted holes arranged in the long axis direction are the same.
In addition, the diameter of the tufting hole is the diameter if the tufting hole is circular in shape when viewed from the front, and if the tufting hole is not circular in shape when viewed from the front, it is the circumcircle of the tufting hole when viewed from the front. is the diameter of

In the present invention, the ratio of the total number of large-diameter tufting holes with a diameter of 1.8 mm or more to the total number of tufting holes provided on the tufting surface (hereinafter also referred to as "ratio Q ₁ ") is 10% or more. In the toothbrush 1 of this embodiment, the ratio _Q1 is 34%. By setting the ratio _Q1 to 10% or more, the feeling of massaging the gums becomes higher. The upper limit of the ratio _Q1 is 100%.
The lower limit of the ratio _Q1 is 10% or more, preferably 20% or more, and more preferably 30% or more. The upper limit of the ratio _Q1 is 100%, preferably 80% or less, more preferably 50% or less, and even more preferably 40% or less. The ratio _Q1 is preferably 10 to 80%, more preferably 20 to 50%, and even more preferably 30 to 40%. This makes it possible to simultaneously massage the gums and clean plaque.

In the present invention, it is preferable that the ratio of the total number of tufting holes with a diameter of 2.0 mm or more to the total number of tufting holes provided on the tufting surface is 10% or more. It is more preferable that the ratio of the total number is 20% or more, and it is still more preferable that the ratio of the total number of tufted holes having a diameter of 2.0 mm or more is 30% or more. This makes it easier to feel the sensation of massaging your gums.

In the toothbrush of the present invention, at least one set of large-diameter tuft holes adjacent to each other in the longitudinal direction has a stress generation parameter P expressed by the following equation ₁ , and a longitudinal stress relaxation parameter P expressed by the following equation 2 of 1. ₂ (hereinafter also referred to as "ratio Q ₂ ") is 20 to 30% (hereinafter also referred to as "condition I").
P ₁ = (S _A - S _B ) x h ... Formula 1
P ₂ =S _C ×D ...Formula 2

However, in Equations 1 and 2, S _A is the area (mm ² ) of the circumcircle of a flat line driven into a large-diameter tufting hole when viewed from the front. S _B is the opening area (mm ² ) of the large-diameter tufting hole. h is the distance (mm) from the tufting surface to the lower end of the flat wire driven into the large-diameter tufting hole when viewed from the side. S _C is the area of the flocking surface surrounded by the opening edge of each large-diameter flocking hole adjacent in the longitudinal direction and two tangent lines that touch and do not intersect any of the adjacent large-diameter flocking holes. (mm ² ). D is the thickness (mm) of the head portion.

When the diameters of large-diameter tufting holes that are adjacent to each other in the long axis direction are different, S _A , S _B and h used for calculating the stress generation parameter P ₁ are set for the tufting hole with the larger diameter and the flat line, respectively. Adopt the value of .
When the thickness of the head part changes in the long axis direction, the thickness D used for calculating the long axis stress relaxation parameter _P2 is the thickness D used for calculating the long axis stress relaxation parameter P2. Adopt the thickness of the head part.

In the toothbrush 1 of this example, in the two large-diameter first tuft holes 11a that are adjacent to each other in the head portion 10 so that their centers are aligned on a straight line parallel to the longitudinal direction, for example, as shown in FIG. When the head portion 10 is viewed from the front, the area (mm ² ) of the circumcircle of the flat wire 20 driven into the large-diameter first tufting hole 11a is defined as S _A . The opening area of the large-diameter first tufting hole 11a is assumed to be S _B. Surrounded by the opening edge of each large-diameter first tufting hole 11a adjacent in the longitudinal direction and two tangent lines k1 and k2 that touch any of the adjacent large-diameter first tufting holes 11a and do not intersect. The area (mm ² ) of the flocked surface 10a is S _c . As shown in FIG. 5, in a side view of the head portion 10, the distance (mm) from the flocking surface 10a to the lower end of the flat wire 20 driven into the large-diameter first flocking hole 11a is h.

In a portion near the tip or rear end of the head portion 10, two large-diameter first tuft holes 11a are arranged adjacent to each other in the longitudinal direction with their centers not aligned on a straight line parallel to the longitudinal direction. Then, S _A , S _B , and h are the same as in the above case. In addition, as shown in FIG. 6, two opening edges of the large diameter first tuft holes 11a adjacent to each other in the longitudinal direction and two adjacent large diameter first tuft holes 11a that are in contact with each other and do not intersect with each other are provided. The area (mm ² ) of the flocked surface 10a surrounded by book tangents k3 and k4 is S _c .

In the present invention, at least one set of all combinations of large-diameter tuft holes adjacent in the longitudinal direction satisfies condition I. All combinations of large-diameter tufting holes adjacent to each other in the longitudinal direction may satisfy condition I, or combinations that satisfy condition I and combinations that do not satisfy condition I may coexist.
The ratio of the number of combinations of large-diameter tufting holes adjacent to each other so as to satisfy Condition I to the total number of combinations of large-diameter tufting holes adjacent to each other in the longitudinal direction is preferably 30% or more, and 50%. The ratio is more preferably 80% or more, and even more preferably 80% or more. If the ratio is equal to or higher than the lower limit value, even under conditions of a thin head using large-diameter tufting holes, it is easy to obtain the effect of suppressing cracking of the head portion while maintaining the flocking strength and shedding strength. .

The ratio Q ₂ (=(P ₁ /P ₂ )×100) is 20 to 30%, preferably 22 to 30%, more preferably 25 to 30%, and even more preferably 25 to 27%. If the ratio _Q2 is within the above range, cracking of the head portion can be suppressed while maintaining the flocking strength and shedding strength even under conditions of a thin head using large-diameter flocking holes. In general, toothbrushes tend to crack in the long axis direction when the bristles are implanted, but if the ratio _Q2 is within the above range, even if the head is thin with a large diameter bristle hole, long Axial cracking can be sufficiently suppressed.

The stress generation parameter P ₁ is preferably 2.3 to 4.0, more preferably 2.4 to 3.7. If the stress generation parameter _P1 is equal to or greater than the lower limit of the above range, the hanging allowance of the flat wire will be sufficiently large, and sufficient flocking strength and shedding strength will be easily ensured. If the stress generation parameter _P1 is below the upper limit of the above range, it is possible to prevent the hanging allowance of the flat wire from becoming too long or the impact of driving from becoming too large, and even if the wall is thin, it can be It is easy to suppress the occurrence of cracks.

The long axis stress relaxation parameter P ₂ is preferably 6 to 17, more preferably 6 to 14, and even more preferably 7 to 11. If the long-axis stress relaxation parameter _P2 is equal to or higher than the lower limit of the above range, the impact when driving a flat wire is likely to be sufficiently relaxed, and cracking and whitening of the head portion can be suppressed even if the wire is thin. If the long-axis stress relaxation parameter _P2 is below the upper limit of the above range, the spacing between the tufted holes will not become too wide, the hair sparse feeling will not easily occur, and sufficient cleaning power and massage feeling will be easily obtained.

h is preferably 1.1 to 1.8 mm, more preferably 1.3 to 1.7 mm. It is preferable that h is equal to the value obtained by subtracting the radius of the tufted hole from the depth of the tufted hole.

In the toothbrush of the present invention, the condition (hereinafter referred to as "condition II") that at least one of the large diameter tuft holes has a short axis stress relaxation parameter _P3 expressed by the following equation 3 is from 2.0 to 5.5. ).
P ₃ =(S _D ×D)/d...Formula 3

However, in Equation 3, S _D is the area of the flocking surface (mm ² ), from the area S _D1 of the region i surrounded by the two tangents and the edges on both sides, the total opening area of all the tuft holes in the region i that overlap with the region i S _D2 This is the value obtained by subtracting . D is the thickness of the head portion. d is the width of the head portion.
When the width of the head section changes in the major axis direction, d is the distance between the edges of the head section in the minor axis direction on a straight line in the minor axis direction passing through the center of the tufting hole for which _P3 is to be calculated when viewed from the front. Distance.

In this example, as shown in FIG. 7, two tangent lines m1 and m2 drawn parallel to the short axis direction of the large-diameter first tufting hole 11a, and edges 10b on both sides of the head section 10 in the short axis direction, The area (mm ² ) of the flocked surface 10a surrounded by 10c and 10c is defined as _SD .
_SD can be calculated as follows. In a front view of the head part 10, two tangent lines m1 and m2 drawn parallel to the short axis direction and the short axis of the head part 10 touch both sides of the large diameter first tufting hole 11a in the long axis direction. The area (mm ² ) of the region i surrounded by the edges 10b and 10c on both sides in the direction is S _D1 . The total opening area (mm ² ) of all the first tuft holes 11a and the second tuft holes 11b in region i is defined as S _D2 . For the first tufting hole 11a and the second tufting hole 11b, where only a part of the tufting hole is within the area i, only the area of the part that overlaps with the area i out of the opening area of the opening end of the tufting hole is S. Used for calculating _D2 . S _D is calculated by subtracting S _D2 from S _D1 .

In the present invention, at least one of the large-diameter tuft holes satisfies condition II. All of the large-diameter tuft holes may satisfy Condition II, or there may be a mixture of large-diameter tuft holes that satisfy Condition II and large-diameter tuft holes that do not satisfy Condition II.
The ratio of the total number of _SD patterns satisfying Condition II to the total number of possible _SD patterns is preferably 30% or more, more preferably 50% or more, and even more preferably 80% or more. If the ratio is equal to or greater than the lower limit, it will be easy to obtain sufficient cleaning power and a massage feeling while suppressing cracks in the short axis direction.
In addition, when viewed from the front, the centers of the tuft holes are on the same straight line parallel to the short axis direction, and there are two or more large-diameter tuft holes for which the area i when calculating _SD is the same. When counting the "total number of possible _SD patterns," these large-diameter tuft holes are collectively counted as one _SD pattern.

The short axis stress relaxation parameter P ₃ is preferably 2.0 to 5.5, more preferably 3.0 to 5.0, even more preferably 3.5 to 4.5. Generally, when brushing with a toothbrush, the head part is bent in the long axis direction, so cracks tend to occur in the short axis direction. However, if the short axis stress relaxation parameter _P It is easy to sufficiently suppress cracking in the direction. If the short-axis stress relaxation parameter _P3 is below the upper limit of the range, the spacing between the tufted holes will not become too wide, the sparse feeling will not occur easily, and sufficient cleaning power and massage feeling will be easily obtained.

In the toothbrush 1 of this example, when a straight line parallel to the short axis direction passing through the center of the large-diameter first tufting hole 11a is drawn in front view for all the large-diameter first tufting holes 11a, those straight lines 50% or more of the total number of straight lines are straight lines that do not pass through the center of the small-diameter second tufting hole 11b. In the present invention, when forming large-diameter tuft holes and small-diameter tuft holes on the tuft surface of the head part, as in this example, all the large-diameter tuft holes are When straight lines parallel to the minor axis direction are drawn through the center of the tuft, it is preferable that 50% or more of the total number of these straight lines do not pass through the center of the small diameter tuft hole.
In addition, the above-mentioned "does not pass through the center of the small diameter tuft hole" means that the large diameter tuft hole does not pass through the center of the large diameter tuft hole in the long axis direction of the toothbrush, centered on a straight line parallel to the short axis direction passing through the center of the large diameter tuft hole. This means that the center of the small-diameter tuft hole does not exist within the region formed when the tuft is evenly translated in a width of 20% of the diameter of the tuft hole.
In addition, when viewed from the front, if the centers of two or more large diameter tuft holes are on the same straight line parallel to the short axis direction, a straight line parallel to the short axis direction passing through the centers of those large diameter tuft holes. are the same, so when counting the total number of straight lines, they are counted as one.
In addition, in the measurement of the total number of possible S _D patterns and the total number of straight lines, "being on the same straight line" means a straight line parallel to the short axis direction passing through the center of the large diameter tufting hole. The center of another large-diameter tufting hole exists within a region formed when the toothbrush is equally translated in the longitudinal direction of the toothbrush with a width of 20% of the diameter of the large-diameter tufting hole. It means that.

When a large-diameter tufting hole is provided, the head portion is more likely to break in the short axis direction than when a small-diameter tufting hole is provided. In addition, when a large-diameter tuft hole and a small-diameter tuft hole are combined, the number of holes tends to be larger than when only a large-diameter tuft hole is used. Because there is a difference in the stress applied to small-diameter tufted holes adjacent to each other, distortion is likely to occur. Therefore, if a large-diameter tufted hole is combined with a small-diameter tufted hole, the head portion tends to be more likely to break. On the other hand, the large-diameter tuft holes and the small-diameter tuft holes are shifted in the short axis direction so that 50% or more of the total number of straight lines are straight lines that do not pass through the center of the small-diameter tuft holes. By forming this, cracks in the short axis direction of the head portion can be easily suppressed. The ratio is more preferably 70% or more, and even more preferably 90% or more.

The overall length of the handle body 1a can be appropriately determined in consideration of operability and the like, and is, for example, about 100 to 200 mm.

The material of the handle body 1a is preferably a resin having a bending elastic modulus (JIS K7171) of 1500 MPa or more. The bending elastic modulus of the resin used as the material of the handle body 1a is more preferably 1500 MPa or more and 3000 MPa or less, and even more preferably 2000 MPa or more and 2700 MPa or less. If the bending elastic modulus of the resin is greater than or equal to the lower limit, warping of the head portion 10 is likely to be suppressed. If the bending elastic modulus of the resin is less than or equal to the upper limit value, the neck portion 12 is appropriately bent during brushing, thereby improving the feeling of massaging the gums. In addition, the ability of the bristles to follow the tooth row can be improved, making it possible to brush teeth efficiently.

Examples of preferable resins used as the material of the handle body 1a include polypropylene (PP), polyacetal (POM), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), and polycyclohexylene dimethylene terephthalate (PCT). POM is particularly preferred in this respect.

The number of resins used as the material for the handle body 1a may be one or two or more.
The handle body may be partially or entirely coated with a flexible resin such as an elastomer to improve gripability. The flexible resin is preferably an olefin-based elastomer if the handle body is made of PP, and a styrene-based elastomer is preferred if the handle body is made of POM, from the viewpoint of improving adhesiveness.

The material of the bristles is not particularly limited, and may include polyamide (6-12 nylon, 6-10 nylon, 12-nylon, etc.), polyester (polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, etc.), polyolefin (polypropylene, etc.) ), synthetic resin materials such as elastomers (olefin-based, styrene-based, etc.), and natural materials. The bristles 15 may be made of one kind or two or more kinds of materials.

The cross-sectional shape of the bristles is often circular, but is not limited to the circular shape, and may be triangular, quadrangular, hexagonal, petal-shaped, etc., or a combination of these shapes. The appearance shape of the entire bristles is not particularly limited, and bristles processed into a wave, twist, jagged shape, etc. can also be used.

The diameter of the bristles is preferably 3 to 12 mils (0.076 to 0.305 mm), more preferably 5 to 10 mils (0.127 to 0.254 mm). It is preferable to implant bristles with a small diameter into the large-diameter tuft holes. As a result, even thick bristles can be bent during brushing, and a toothbrush with a high sensation of massaging the gums can be provided.
In addition, the diameter of the bristles is the diameter when the cross-sectional shape of the bristles is circular, and when the cross-sectional shape of the bristles is other than circular, it is the diameter of the circumscribed circle of the cross-section of the bristles.

The bristles may be regular bristles that have approximately the same diameter within one bristles except for the rounded portion of the bristles. Note that the tapered bristles may have the above-mentioned thickness near the bristled surface 10a of the head portion 10, and be sharpened so that the diameter gradually becomes thinner toward the tip of the bristles. In this case, the tips of the bristles can easily penetrate into the gaps between the teeth and provide a soft touch, making it suitable for cleaning the cervical region of the teeth and massaging the gums. In addition, normal hair and tapered hair can be appropriately selected for each hair transplant hole, mixed within the same hair bundle, or freely combined.

The length of the bristles from the flocked surface 10a (hair length) can be set as appropriate, and is, for example, about 6 to 15 mm. The length of the hair for adults is preferably 9 mm to 15 mm, and for children 6 mm to 9 mm.
The diameters of the first bristle bundle 16a and the second bristle bundle 16b may be set according to the diameters of the first tuft hole 11a and second tuft hole 11b to be implanted.

As explained above, in the toothbrush of the present invention, since the head portion has a thin thickness of 2 mm or more and 4 mm or less, it has excellent operability in the oral cavity and is highly effective in cleaning molars and the like. Furthermore, since the ratio _Q1 of tuft holes with a diameter of 1.8 mm or more is 10% or more, various effects can be obtained by implanting large-diameter tufts of hair, such as increasing the feeling of massaging the gums.

In addition, when large-diameter tuft holes are arranged in the longitudinal direction of a thin head section and large-diameter tuft holes, which are subjected to a large impact on the head section during tufting, cracking and whitening tend to occur particularly easily. On the other hand, in the toothbrush of the present invention, two or more large-diameter bristle holes are formed in the longitudinal direction while controlling the ratio Q ₂ of the stress generation parameter P ₁ to the longitudinal stress relaxation parameter P ₂ within a specific range. Arrange. Therefore, while suppressing the occurrence of cracking and whitening of the head portion, sufficient fixing force of the hair bundle by the flat wire can be ensured, and high hair-planting strength and hair-shedding strength can be obtained.

Note that the toothbrush of the present invention is not limited to the toothbrush 1 described above.
For example, in the toothbrush of the present invention, the number of bristle bundles planted on the bristle-planting surface of the head portion and the arrangement pattern of the bristle-planting holes are not limited to those of the toothbrush 1. Specifically, the number of bristle bundles and the arrangement pattern of the tuft holes in the toothbrush of the present invention may be in the form of the toothbrushes 1A to 1G illustrated in FIGS. 9 to 15.
As shown in FIG. 16, the toothbrush 1H of the present invention has a small-diameter second bristle-filling hole 11b arranged on the outside in the short-axis direction, and a large-diameter first bristle-filling hole 11a arranged inside in the short-axis direction. It may be.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited by the following description.
[Evaluation of ease of cleaning back teeth]
A sensory test was conducted by a panel of 10 experts, and the ease of cleaning back teeth (second molars) was evaluated using the following criteria. If the average score of 10 expert panelists is 4.0 points or more and 5.0 points or less, "◎", 3.0 points or more and less than 4.0 points is "○", 2.0 points or more, 3.0 points. Scores of less than 2.0 points were scored as "△", and scores of less than 2.0 were marked as "x". Those with a rating of ○ or ◎ were judged to be toothbrushes that were easy to clean back teeth.
(Evaluation criteria)
5 points: Very easy to polish.
4 points: Slightly easy to polish.
3 points: Neither.
2 points: Slightly difficult to polish.
1 point: Very difficult to polish.

[Experience of removing plaque]
A sensory test was conducted by a panel of 10 experts, and the feeling of removing plaque was evaluated using the following criteria. If the average score of 10 expert panelists is 4.0 points or more and 5.0 points or less, "◎", 3.0 points or more and less than 4.0 points is "○", 2.0 points or more, 3.0 points. Scores of less than 2.0 points were scored as "△", and scores of less than 2.0 were marked as "x". Those with a rating of ○ or ◎ were judged to be toothbrushes that were highly effective at removing plaque.
(Evaluation criteria)
5 points: I feel it very much.
4 points: Somewhat felt.
3 points: Neither.
2 points: I don't feel it much.
1 point: I don't feel it at all.

[Evaluation of gum massage experience]
A sensory test was conducted by a panel of 10 experts, and the sensation of massaging the gums was evaluated using the following criteria. If the average score of 10 expert panelists is 4.0 points or more and 5.0 points or less, "◎", 3.0 points or more and less than 4.0 points is "○", 2.0 points or more, 3.0 points. Scores of less than 2.0 points were scored as "△", and scores of less than 2.0 were marked as "x". Those with a rating of ○ or ◎ were judged to be toothbrushes that were highly effective in massaging the gums.
(Evaluation criteria)
5 points: I feel it very much.
4 points: Somewhat felt.
3 points: Neither.
2 points: I don't feel it much.
1 point: I don't feel it at all.

[Evaluation of head cracking and whitening]
Using a Zahoransky flocking machine, 100 toothbrushes were made with flocked hair on the head, and a specialized inspector visually detected the number of cracks and whitening that occurred on the head, and calculated the number of bristles for 100 toothbrushes. The value (percentage) divided by the number of pores was used as the evaluation standard for whitening. Cracking and whitening of the head portion were evaluated based on the following criteria.
(Evaluation criteria)
◎: 0%.
○: Greater than 0% and less than 0.1%.
△: 0.1% or more and less than 0.5%.
×: 0.5% or more.

[Difficulty in shedding hair bundles]
Grasp the hair bundle implanted in one large-diameter implant hole with a special instrument, and measure the maximum tensile stress (N) until the hair bundle comes out from the implant hole using a tensile tester (pulling speed 20 mm/min). (n=10), and the difficulty of hair strands falling out was evaluated according to the following criteria.
(Evaluation criteria)
◎: Average value of maximum tensile stress is 25N or more.
○: Average value of maximum tensile stress is 20N or more and less than 25N.
Δ: Average value of maximum tensile stress is 15N or more and less than 20N.
×: Average value of maximum tensile stress is less than 15N.

[Example 1]
Using POM (bending modulus of elasticity: 2500 MPa) as the resin forming the handle body, the handle body 1a illustrated in FIGS. 1 to 8 was produced by injection molding according to the specifications shown in Tables 1 and 2. Fold a bundle of hair made by Toray Monofilament Co., Ltd. (diameter: 5.0 mil large hole, 6.0 mil small hole) in half, and insert the flat wire sandwiched between them into the tuft hole in the head according to the specifications shown in Table 2. A toothbrush was made by hammering and planting the hair strands.

[Examples 2 to 4, Comparative Examples 1 to 4]
A toothbrush was produced in the same manner as in Example 1, except that the specifications of the tufting holes and the flat wire were changed as shown in Tables 1 and 2.

The specifications of the toothbrushes of each example are shown in Tables 1 and 2, and the evaluation results are shown in Table 3. Note that the specifications of the tufted holes and flat wires in Examples 1, 2, and 4 and Comparative Examples 1 and 2 in Table 2 are shown only for large-diameter tufted holes. Further, in the P ₁ , P ₂ and Q ₂ columns of Comparative Examples 3 and 4 in Table 2, values calculated for small-diameter tuft holes instead of large-diameter tuft holes are shown.

As shown in Tables 1 to 3, the toothbrushes of Examples 1 to 4, in which the thickness of the head part, ratio Q ₁ and ratio Q ₂ were controlled within the range specified by the present invention, had suppressed cracking and whitening of the head part. In addition, sufficient flocking strength was ensured. In addition, it was easy to clean the back teeth, the feeling of removing plaque was high, and the feeling of massaging the gums was also high.
In Comparative Examples 3 and 4 where the ratio Q ₂ was high and the stress generation parameter P ₁ was low, the risk of cracking and whitening of the head portion increased, and the hair shedding strength tended to decrease. Moreover, the toothbrushes of Comparative Examples 3 and 4, which did not have large-diameter tuft holes with a diameter of 1.8 mm or more, lacked the feeling of massaging the gums compared to the Examples. In Comparative Examples 1 and 2, in which the head portion was too thick, it was difficult to clean the molars compared to the Example.

DESCRIPTION OF SYMBOLS 1... Toothbrush, 1a... Handle body, 10... Head part, 10a... Flocking surface, 10b, 10c... Edge, 11a... First flocking hole, 11b... Second flocking hole, 12... Neck part, 14... Handle part, 16a ...First hair bundle, 16b...Second hair bundle, 18...Flush part, 20...Flat line.

Claims (4)

A toothbrush comprising a handle body made of resin including a head portion with a plurality of tuft holes provided on the tuft surface, and each of the tuft holes is provided with a bristle part in which a bundle of hair is implanted by driving a flat wire. There it is,
The thickness of the head portion is 2 mm or more and 3.5 mm or less,
The ratio of the total number of large-diameter tufting holes with a diameter of 1.8 mm or more to the total number of tufting holes provided on the tufting surface is 10% or more,
Two or more of the large diameter tuft holes are arranged in the longitudinal direction of the handle body,
At least one set of the large-diameter tuft holes adjacent in the longitudinal direction has a ratio of stress generation parameter P ₁ expressed by the following formula 1 to the longitudinal stress relaxation parameter P 2 expressed by the following formula ₂ from 20 to Satisfying the condition that it is 30%,
In a side view of the head part, the distance h from the flocking surface to the lower end of the flat wire driven into the large diameter flocking hole is 0.46 or less as a ratio to the depth of the large diameter flocking hole. , toothbrush.
P ₁ = (S _A - S _B ) x h ... Formula 1
P ₂ =S _C ×D ...Formula 2
(However, in the above formulas 1 _and 2, S _A is the area (mm ² ) of the circumcircle of the flat line driven into the large diameter tufting hole when viewed from the front. is the opening area (mm ² ) of the tufting hole. h is the distance (mm) from the tufting surface to the lower end of the flat wire driven into the large diameter tufting hole in side view. _SC is , the area of the flocking surface surrounded by the opening edge of each of the large-diameter flocking holes adjacent in the longitudinal direction and two tangents that touch and do not intersect any of the adjacent large-diameter flocking holes ( mm ² ). D is the thickness (mm) of the head portion.) The toothbrush according to claim 1, wherein the stress generation parameter P ₁ is 2.3 to 4.0. The toothbrush according to claim 1 or 2, wherein at least one of the large-diameter tufting holes satisfies the condition that a short-axis stress relaxation parameter P ₃ expressed by the following equation 3 is 2.0 to 5.5.
P ₃ =(S _D ×D)/d...Formula 3
(However, in the above formula 3, S _D is the flocking surface surrounded by two tangent lines drawn parallel to the short axis direction of the large diameter flocking hole and the edges on both sides of the head section in the short axis direction. The area (mm ² ) of region i surrounded by the two tangent lines and the edges on both sides _S ( _D is the thickness (mm) of the head portion. d is the width (mm) of the head portion.) The large-diameter tufting hole and the small-diameter tufting hole having a diameter of less than 1.8 mm are formed on the tufting surface,
For all the large-diameter tuft holes, when a straight line is drawn parallel to the minor axis direction passing through the center of the large-diameter tuft hole when viewed from the front, the straight line is 50% or more of the total number of these straight lines. The toothbrush according to any one of claims 1 to 3, wherein is a straight line that does not pass through the center of the small diameter tuft hole.

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